Yep, it was funk, thanks!
(I still have some cleanup work to do; I plan to transfer some of the “temporary page” organization to the normal wiki, and maybe restructure the log.)
So it turns out that bthom wanted a cross-compiler rather than a compiler, and I think the previous backend was written as a compiler (intended to be built itself within qemu). Most of the effort went into him discovering how to hack the ./configure for cross-compilation (we looked at how @whitequark does his cross-compilation trees but they directly contain the post-configuration output, and you still need to first play with ./configure to figure out what those outputs should do). Finally, he wanted to run bare-metal RISC-V program, so last I know he was gutting out the parts of the (target) runtime depending on dirent.h and other OS things. I don’t think that much actual testing was done (the one part of ./configure that actually execute binaries was run under spike, if that counts), but hopefully that could happen in the future.